1. Field of the Invention
The invention relates to a wheel-guiding spring strut, optionally with internal ride-height control or level regulation, comprising a shock strut optionally constructed as a self-pumping hydropneumatic spring strut, a piston rod supported at an upper supporting bearing, and a coil spring which is fixed between the spring strut and the supporting bearing at a spring plate.
2. Discussion of the Prior Art
In known wheel-guiding spring struts with integrated level regulation and a mechanical auxiliary spring (see German reference DE 36 30 757 C2), the differences in position caused by load are compensated by the change in the hydropneumatic spring forces acting along the piston rod, so that the carrying part of the mechanical auxiliary spring remains practically unchanged. However, this also impairs the compensation of transverse force effected via the mechanical auxiliary spring; namely, when load is increased relative to the fully compensated design state, this leads to an undercompensation, while a decreased load leads to overcompensation.
Further, wheel-guiding spring struts are known, wherein increased lateral forces due to the bending moment to be supported occur in the piston rod guide and at the damping piston. These increased lateral forces generate uncomfortable friction forces in the suspension movements of the spring strut. Such a disadvantage is compensated by a balancing or compensation of transverse forces (e.g., German reference DE 14 30 586 A1). In this case, the coil spring is installed so as to be partially transversely clamped in order to achieve a spring force extending obliquely relative to the damper axis. However, this compensation is carried out only in a determined preferred position, usually in the so-called design position, so that a complete compensation of the bending moment, and therefore of the lateral forces, takes place only in this design position. The compensation effect is accordingly load-dependent and position-dependant, so that the compensating action does not take effect outside of the design position. The eccentric offset of the spring plate or transversely-clamped installation of the spring is meant to influence the spring force direction and spring force position so that the bending moment on the spring strut resulting from the wheel support with the known disadvantageous consequences, i.e., lateral forces, friction and wear on the linkage and piston, is completely or partially compensated in the normal position of the vehicle.